I. Teleconferencing
Conventional Television and TV cable broadcasting is generally carried out on a real-time basis. For instance, it takes the same length of time to broadcast or transmit a TV program than it does to receive and display the program. Such broadcasting method has proven to be less than completely desirable due to limited TV bandwidth and channels allocation therein.
Channel availability has been a crucial limitation in the broadcasting industry. Channel allocation has been very valuable and expensive. It has precluded several interested persons, small businesses, consumers and local community chapters from accessing the TV broadcasting networks.
TV broadcasting has become the single most important and popular means for accessing and educating large numbers of citizens. Therefore, TV broadcasting has a direct effect on the right to free speech and expression as guaranteed by several constitutions around the world, including that of the United States of America.
Research and development has been carried out in the TV and video broadcasting field. The United States Department of Defense has sponsored several projects relating to the field of the present invention. The following Defense Technical Information Center (DTIC) technical reports exemplify some of these projects:                1. AD-A210 974, entitled “Robot Vehicle Video Image Compression.”        2. AD-A191 577, entitled Narrative Compression Coding for a Channel with Errors.”        3. AD-A194 681, entitled “SNAP/DDN Interface for Information Exchange.”        4. AD-A174 316, entitled “A Packet Communication Network Synthesis and Analysis System.”        5. AD-A206 999, entitled “Geometric Methods with Application to Robust Detection and Estimation.”        6. AD-A207 814, entitled “Random Transform Analysis of a Probabilistic Method for Image Generation.”        7. AD-A188 293, entitled “A Video-Rate CCD Two-Dimensional Cosine Transform Processor.”        8. AD-A198 390, entitled “Navy Satellite Communications in the Hellenic Environment.”        9. AD-A206 140, entitled “Investigation of Optional Compression Techniques for Dither Coding.”        
The following patents are incorporated by reference and teach various video broadcasting and teleconferencing techniques:                1. U.S. Pat. No. 3,693,090 to Gabriel, entitled “Wired Broadcasting Systems”, and assigned to Communications Patents Limited.        2. U.S. Pat. No. 3,733,430 to Thompson et al., entitled “Channel Monitoring System”, and assigned to RCA Corporation.        3. U.S. Pat. No. 4,215,369 to Ijima, entitled “Digital Transmission”, and assigned to Nippon Electric of Japan.        4. U.S. Pat. No. 4,300,161 to Haskell, entitled “Time Compression Multiplexing of Video Signals”, and assigned to Bell Telephone Laboratories.        5. U.S. Pat. No. 4,650,929 to Boerger et al., entitled “Communication System For Videoconferencing”, and assigned to Heinrich Hertz Institute of Germany.        6. U.S. Pat. No. 4,903,126 to Kassatly, entitled “Method and Apparatus for TV Broadcasting”.        7. U.S. Pat. No. 4,975,771 to Kassatly, also entitled “Method and Apparatus for TV Broadcasting”.        8. U.S. Pat. No. 4,410,980 by Takasaki, entitled “Time Division Multiplexing System”, and assigned to Hitachi Limited of Japan.        9. U.S. Pat. No. 4,533,936 by Tiemann, entitled “System for Encoding and Decoding Video Signals”, and assigned to General Electric Co.        10. U.S. Pat. No. 4,593,318 by Eng, entitled “Technique for the Time Compression Multiplexing of Three Television Signals”, and assigned to AT&T Bell Laboratories.        11. U.S. Pat. No. 4,646,135 by Eichelberger, entitled “System for Allowing Two Television Programs Simultaneously to Use the Normal Bandwidth for One Program by Chrominance Time Compression and Luminance Bandwidth Reduction”, and assigned to General Electric Co.        12. U.S. Pat. No. 4,442,452 by Powell, entitled “Image Processing Method Using a Block Overlap Transformation Procedure”, and assigned to Eastman Kodak.        
The Boerger 4,650,929 patent is a representative publication of the state of the relevant art in the video teleconferencing field, and will now be described in more detail. The Boerger patent generally relates to a video-conferencing system which basically includes a central station 1 and a significantly limited number of subscribers stations 25. Boerger acknowledges the limitation of the patented system in column 3, lines 41-43, and column 7, lines 51-52, and states that it only accommodates a maximum of 12 subscribers. Furthermore, the main purpose of the central station appears to be that of “an intermediary or exchange between sources and sinks, i.e. transmitting and receiving signal points”. Column 3, lines 10-13.
Therefore, the Boerger system, in general, seems to connect only a very limited number of specific subscribers; collects the video and audio signals from these subscribers in the central station; and sends the collected signals back to the subscribers. These signals are sent back to the subscribers in a non-compressed format, on a real time basis.
FIG. 4, and the corresponding description of the system in the specification, column 7, lines 15-18, lines 29-33 and lines 54-62; and column 9, lines 53-58, indicate that the incoming video source signals 41 are passed through an analog-to-digital converter 9 to a large picture storage 5, and to a small picture storage 6. The video signals from the large and small picture storages 5 and 6 are then fed to multiplexers 17, 18, and therefrom, through a digital-to-analog converter 19 to the respective connecting line 36. Therefore, the video signals are converted back to analog signals prior to transmission to the participant subscribers, and as such the signals are said to be transmitted on a real-time basis, and are not compressed. Consequently, there is no need to decompress the video signals at the participant subscribers' locations 25. Please refer to column 3, lines 24-27, which confirm that “[if] picture storage units and multiplexers are employed for video signals in digital form, conventional networks can be used, as before, equipped for transmitting analog signals.”
The gist of the Boerger system therefore seems to be the use of conventional cameras and monitors at the participant locations, as well as “control means which can be manipulated to initiate communication with other participants and to control the images displayed.” Column 2, lines 37-39. The signals 42 which are transmitted to the participant locations 25 already contain the composite mixture of large and small pictures as selected by the location 25, and consequently, the location 25 does not include means for demultiplexing and decompressing the signals.
Furthermore, while Boerger mentions the use of multiplexers, he did not teach any discipline for conducting the multiplexing of the video signals. It appears that Boerger is simply equating multiplexing with mixing of signals from the large and small picture storages 5 and 6.
Additionally, the limited capability of the Boerger system renders it similar to a closed loop system, and if the maximum number of subscribers (12 subscribers) are using the system, other participants will be locked out, and will not be able to join in or to establish their own video-conferencing session. This is a significant limitation, as it renders the Boerger system generally inefficient as a public video tele-conferencing system.
As a quasi-closed loop, private video conferencing system, Boerger is not concerned with and does not address the issue of video channel availability. For all practical purposes, each one of the large and small picture signals can be assigned its own transmission bandwidth (column 3, lines 30-40), without regard to the compression requirements. This holds particularly true if the connecting lines 36 and return channels 37 are actual cable lines as opposed to television or satellite telecommunications channels.
Therefore, it would be highly desirable to have a new and improved method and apparatus for video teleconferencing and for increasing video channel availability and for rendering the video channel allocation process more efficient. The new method and apparatus should be relatively simple and inexpensive to implement and to place into effect. The new method and apparatus should also be capable of being implemented with new as well as existing television or receiver sets.
II. Video Cameras
The first generation of color studio cameras used three image orthicon tubes, which were essentially three identical monochrome camera channels with provisions for superposing the three output-signal rasters mechanically and electrically. The optical system consisted of a taking lens which was part of a four-lens assembly. The scene was imaged in the plane of a field lens using a 1.6-inch diagonal image format. The real image in the field lens was viewed by a back-to-back relay lens assembly of approximately 9 inch focal length. At the rear conjugate distance of the optical relay was placed a dichromic-prism beam splitter with color-trim filters.
In this manner, the red, blue, and green components of the screen lens were imaged on the photo-cathodes of the three image orthicon tubes. A remotely controlled iris located between the two relay-lens elements was used to adjust the exposure of the image orticons. This iris was the only control required in studio operation. These cameras are no longer in use because of their size, cost, and operating and setup requirements, compared to photoconductive cameras.
Four-tube (luminance-channel) cameras were then introduced when color receivers served a small fraction of the audience. The viewer of color program in monochrome became aware of lack of sharpness. Using a high-resolution luminance channel to provide the brightness component in conjunction with three chrominance channels for the Red (R), Green (G) and Blue (B) components produced images that were sharp and independent of registry errors.
Improvements in scanning components and circuits have eliminated the need for use of a separate luminance channel in order to obtain adequate resolution. However, for a period of time, the four-tube approach continued to be used for telelcine applications where the inclusion of an additional vidicon channel was not an appreciable cost consideration or of mechanical complexity. Nevertheless, the four-tube cameras were supplanted by the three-tube photoconductive cameras and by non-storage flying-spot and charge coupled device scanning systems.
A color television camera must produce R, G and B video signals which complement the characteristics of the NTSC three-gun three-phosphor standard additive display tube. For both live and film cameras it is now common to use a camera with three photoconductive pickup tubes with a high-efficiency dichromic light splitter to divide the optical image from a zoom lens into three images of red, blue and green, with different spectral characteristics.
Light splitting is accomplished by a prism or by a relay lens and dichromic system. The prism has the advantage of small size and high optical efficiency but a disadvantage in that the three tubes are not parallel to each other and are thus more susceptible to misregistration produced by external magnetic fields. A more serious problem is that of obtaining a uniform bias light on the face of the tubes. Bias light producing 2 to 10 percent of the signal is used in most modern cameras to reduce lag effects. Nonuniformity of the bias light can produce color shading in dark areas of the picture. Most new designs now use the prism splitter.
Therefore, it would be highly desirable to have a new video camera that does not use multiple color optical splitters, and which improves the sharpness and resolution of the image.
One of the most important criteria for determining the picture quality of a color television camera is the signal-to-noise ratio, which is measured in decibels according to the following formula:dB=20.log[peak-to-peak video voltage/rms noise voltage]. 
Noise also plays an important role in the quality of the video signals transmitted. Several types of radio noise must be considered in any design, though, in general, one type will be the dominant factor. In broad categories, the noise can be divided into two types: noise internal to the receiving system, and noise external to the receiving antenna.
The noise of the receiving system is often the controlling noise in systems operating above 100 MHz. This type of noise is due to antenna losses, transmission-line losses, and the circuit noise of the receiver itself.
Several costly designs, using elaborate mathematical equations, have been devised to reduce the noise factor and to improve the signal-to-noise ratio. However, low-cost circuit designs still include a relatively low signal-to-noise ratio, for cost effectiveness.
Therefore, it would be desirable to have a new circuit design and method for improving signal-to-noise ratio in video broadcasting systems, and particularly in low cost video cameras and broadcasting systems.
III. LCD Monitors
Liquid crystal display (LCD) monitors have become increasingly popular in the television and computer industries. In general, a conventional LCD monitor includes a single rigid screen which permits the display of either video signals or computer generated signals. The following patents illustrates some exemplary conventional liquid crystal display devices and methods of manufacturing the same:                1. U.S. Pat. No. 4,874,227 issued to Matsukawa et al. describes a large-size crystal display which is used as a large picture display for a sign or advertisement at railway stations, airports or for projection at halls or theaters. Matsukawa teaches the use of a single unitary rigid large size display of fixed dimensions and size.        2. U.S. Pat. No. 4,806,922 issued to McLaughlin et al. generally describes a large size LCD having several nematic curvilinearly aligned phases (NCAP) liquid crystal material. The modules are positioned adjacent to one another to effect a single display having a relatively large area. The McLaughlin patent is incorporated herein by reference.        3. U.S. Pat. No. 4,597,058 issued to Joseph et al. discloses a large liquid crystal display electronic sign which employs several modules that are juxtaposed adjacent to one another on a transparent diffuser plate and a conducive liquid crystal coating layer between the plates.        4. U.S. Pat. No. 4,832,457 to Saitoh et al., assigned to Hitashi Limited of Japan, and entitled Multipanel Liquid Crystal Display Device”, relates to a method of manufacturing the LCD, by combining two or four LCD panels to increase the displayable area.        
Liquid crystals are also defined in several publications, among which is the “Electronics Engineers' Handbook”, Third Edition, McGraw Hill Publications, page 6-36, where a general brief explanation of the use of liquid crystal displays in television, is given at page 20-120.
However, conventional liquid crystal monitors still include a single screen which does not enable the user to select the desired sizes and shapes of the screen. The size and weight of a LCD monitor are important features for the LCD to compete with other displays, and printed publications such as newspapers. For this purpose, the monitor should be small in size and light in weight. Additionally, conventional displays, including lap top computers, are generally inconvenient to transport, since the screen is a single rigid screen which commonly folds over the keyboard.
Furthermore, conventional displays do not generally address the growing elderly and disabled populace, who would be very inconvenienced by the fixed size of the conventional display monitors. At present, these monitors do not enable this group of people to accommodate the displayed material to their own personal needs. In some instances, an elderly person might wish to read a newspaper, but is prevented from doing so because of that person's inability to read small print characters, and to hold and flip through the relatively heavy paper.
Therefore, it would be desirable to have a display monitor which uses liquid crystal material, and which could be sized and dimensioned by the user according to the user's particular needs.
IV. Paperless Network
At present, information is widely spread and distributed by means of publications such as newspapers, books and magazines. Generally, publications are distributed individually to subscribers in a relatively cumbersome, costly and inefficient way. Furthermore, the reader or subscriber usually finds it bulky, cumbersome and inconvenient to carry or transport the printer publication for reading or reviewing it at a later time.
Printed publications can be relatively heavy, and can contain information that is not of particular interest to the reader. Additionally, there is a private and public concern with respect to the manner of disposing of the printed publications once they have been read, and are no longer of use. This constitutes substantial waste of resources, which has instigated attempts to recycle and reuse the paper. Nonetheless, the recycling process does not solve all the foregoing problems.
Some methods have been designed to substitute for the paper dissemination of information, among which are computers, audio and video cassettes, floppy disks and like devices. However, there has been no paperless device or method which substitutes entirely for the paper dissemination of information.
Therefore, there is a substantial need for a new and improved paperless network and method of using the same for disseminating information. The new network and method of using it should substantially reduce or substitute for the use of paper, thus reducing the cost of distribution and waste. The new network should render the transfer, transport, storage and review of published information convenient, and should permit a wasteless disposition thereof.
U.S. Pat. No. 4,597,058, issued to Izumi et al., and U.S. Pat. No. 4,654,799, issued to Ogaki et al. describe software vending machines, it being understood that “software” includes machine readable codes to the exclusion of “human readable” or printed publications.
Software vending machines address distinctly different problems than printed publications. The Izumi vending machine is provides for a cartridge programming system and method for storing a library of programs and for loading a selected program or set of programs onto reprogrammable cartridge memories.
Other objects of the Izumi vending machine are to provide a method of maintaining a program library without requiring a large inventory of memory cartridges; and to provide a system for programming a cartridge memory without removing the semiconductor memory chip from the cartridge.
However, conventional software and other publications vending machines do not yet present an acceptable alternative to printed publications, which deal with different problems, among which are: (1) Inefficient and wasteful distribution of printed publications; (2) Indirect restraint on the United States constitutional freedom of speech; (3) Waste of natural resources; and (4) Environmental concerns.
With the foreseeable depletion of natural resources, such as timber, paper publications will become increasingly expensive to produce. This will eventually force the conventional printing industry to select alternate less expensive routes. After printing, the conventional paper publications are conventionally transported, stored, and distributed at an enormous and wasteful overhead, cost and labor.
Nowadays, small businesses and individuals find it quite prohibitive to advertise and/or to express their views in conventional publications, such as newspapers. As the cost of printed publications rises with the continuing decrease of natural resources, it will become even more forbidding for individuals and small businesses to retain, even the limited access to printed publications, they now enjoy. This problem will become a major concern in the near future, as it will very subtly become an indirect restraint on the constitutional freedom of speech.
Enormous waste of natural resources are presently generated by the use of conventional paper publications. For instance, it is highly unlikely that the subscribers read each and every line or page of their daily newspapers or weekly journals. Despite the huge waste of natural resources, conventional publications methods are still being used to publish newspapers which are not even read in their entirety.
Consider also the environmental issues relating to the waste generated by the conventional paper publications. Recycling is becoming increasingly popular in industrialized countries such as the United States, and other countries are following suit. Recycling bins dedicated to paper are sprouting nationwide, and dumping sites are filling up and becoming harder to locate due to increasing social and environmental pressures.
Therefore, it would be highly desirable to have a new system which will ultimately substitute for the conventional printed publications, and which will render the distribution and dissemination of information efficient and economical, and as such, more accessible to the members of the general public. The new system should eliminate or substantially reduce the current impermissible waste of natural resources which are depleted by the conventional publication industry.
V. Program Delivery System With Digital Compression and Encoding/Decoding Scheme
Methods for digitizing and compressing video signals are well known. The following patents, are incorporated by reference and teach various conventional video digitization and compressing techniques:                1. U.S. Pat. No. 3,740,466 to Marshall et al., entitled “Surveillance System”, relates to a system for maintaining surveillance for detecting changes of interest in the surveilled domain and ignoring other changes. The system employs an analog to digital converter 50 for converting the analog television input signals into a digital format which is stored in the computer memory.        2. U.S. Pat. No. 3,883,685 to Yumde et al., entitled “Picture Signal Conversion System”, and assigned to Hitachi Limited of Japan, relates to a system for converting an analog signal of a wide band into a pulse train signal of a narrow band. The input picture signal is converted into a digital signal and is successively written in the digital memory. When the picture signal of one frame is written in to fill up the digital memory, a write-in end pulse signal is generated by a clock pulse signal generator.        3. U.S. Pat. No. 3,883,686 to Jacobacus et al., entitled “Method to Reduce the Effect of a Loss of Information during the Transmission Compressed Band Width and Device for Carrying out the Method”, and assigned to T. L. M. Ericsson of Sweden, generally relates to a technique for reducing the effect of loss of information during transmission at compressed bandwidth of a PCM-signal. A PCM coder converts the analog video signal to a PCM signal such that the picture elements in the video signal will be the equivalent to PCM words having binary values which are equivalent to respective light intensities of the picture elements.        4. U.S. Pat. No. 4,075,658 to de Cosnac et al,. entitled “Method and Device for Isolating Figures in an image”, and assigned to Commissariat a L'Energie Atomique of France, relates to a method for converting the graphic information in the image to a video signal constituted by a succession of lines, each being sampled sequentially to obtain an ordered series of points which is stored in memory.        5. U.S. Pat. No. 4,079,417 to Scudder, entitled “Digital Video Window Control”, and assigned to General Electric Company, relates to a digital signal processor which is connected between a refresh memory at the output of a digital computer in an x-ray tomography, and the digital to analog converter of a CRT display to provide a limited resolution gray scale display of a selected portion from an image signal having wide dynamic range.        6. U.S. Pat. No. 4,095,259 to Sawagata, entitled “Video Signal Converting System Having Quantization Noise Reduction”, and assigned to Sony Corporation of Japan, relates to a system for converting a video signal into a digitized signal, and for clamping the levels at every horizontal synchronizing interval. The levels are randomly shifted before conversion, whereby quantization noise can be scattered on a displayed image by reclamping after a reconversion of the signal.        7. U.S. Pat. No. 4,124,871 to Morrin, entitled “Image Data Resolution Change and Apparatus and Process Utilizing Boundary Compression Coding of Objects”, and assigned to IBM Corporation, relates to a method for using the information obtained in the boundary following exterior and interior borders of objects, to accomplish resolution or size changing of scanned objects.        8. U.S. Pat. No. 4,127,873 to Katagi, entitled “Image Resolution Enhancement and Apparatus”, and assigned to RCA Corporation, generally relates to the display of a frame of information in the form of a row and column matrix of display elements. The matrix is created from a corresponding group of data cells stored functionally in the form of a row and column, where the number of rows and columns in the stored matrix is less than the number of rows and columns in the displayed matrix.        9. U.S. Pat. No. 4,143,401 to Coviello, entitled “System For Generating Line Drawing of a Scanned Image”, and assigned to Westinghouse Electric, generally relates to scanners for detecting changes in the gray scale of a scanned image to generate line drawing corresponding to changes in the gray scale image. Each line of video information produced by scanning the image is digitized. Each digitized sample is compared to digital samples delayed a predetermined amount to generate a difference signal which is indicative of a change in the gray scale having a component perpendicular to the direction of the scan.        10. U.S. Pat. No. 4,148,070 to Taylor, entitled “Video Processing System”, and assigned to Micro Consultants of England, generally relates to the manipulation of pictures by digital methods in diverse fields. A digital frame store receives and stores digital video signals. A digital to analog converter converts the data back into analog form, and accessing means provides random access to the frame store locations during the video blanking time to allow processing of the data.        11. U.S. Pat. No. 4,183,058 to Taylor, entitled “Video Store”, and assigned to 0.20 Micro Consultants of England, generally relates to video digital storage systems. The store may be operated in an asynchronous manner.        12. U.S. Pat. No. 4,189,744 to Stern, entitled “Apparatus for Generating Signals Representing Operator selected Portions of a Scene”, and assigned to New York Institute of Technology, generally relates to an apparatus for generating video-representable signals which represent one or more operator-selected portions of a scene. The apparatus includes means for displaying the tabulation of the pixel values, and an operator can select desired portions of an existing scene and automatically obtain stored contour outlines of those portions.        13. U.S. Pat. No. 4,193,096 to Stoffel, entitled “Half Tone Encoder/Decoder”, and assigned to Xerox Corporation, generally relates to a system for compressing scanned image data. The system subdivides the image data pixel pattern into quadrants encodes pictorial data, by predicting form the established image values of adjoining quadrants, an image value for each quadrant.        14. U.S. Pat. No. 4,242,707 to Budai, entitled “Digital Scene Store”, generally relates to a method for raster scanning a scene. During each scan, an analog signal derived from a binary number and representing a given light intensity is compared against other analog signals representing the light intensity of each of the pixels. When the light intensity of a pixel is greater than the given light intensity, the binary number associated with that given light intensity is stored in registers assigned to the respective pixels. After each scan, the given light intensity is increased.        15. U.S. Pat. No. 4,282,546 to Reitmeier, entitled “Television Image Size Altering Apparatus”, and assigned to RCA Corporation, generally relates to a method for separating composite pixel information into original pixels relating to each basic component of the video signal. Interpolated pixel values are then derived from the original pixel values at an effective rate less than the synchronous rate when compressing the image size, and at an effective rate greater than the synchronous rate when expanding the image size.        16. U.S. Pat. No. 4,302,776 to Taylor et al., entitled “Digital Still Picture Storage System with Size Change Facility”, and assigned to Micro Consultants of England, generally relates to a method for digital picture processing suitable for use in a digital picture library. The system includes real time frame storage and a non-real time store. The size change mechanism has access to the data in the non-real time domain to allow size change techniques to be used.        17. U.S. Pat. No. 4,365,273 to Yamada et al., entitled “Picture Data Compression Method”, and assigned to Dainippon Screen Seiko Kabushiki Kaisha of Japan, generally relates to a method for compressing picture data where an original picture is scanned photoelectrically to obtain analog picture signals which are converted into picture data to be transmitted. Each matrix of picture data is compared with an adjacent picture data in horizontal, vertical, right upper diagonal and left upper diagonal directions to obtain comparisons results.        18. U.S. Pat. No. 4,369,463 to Anastassiou, entitled “Gray Scale Image Data Compression with Code Words a Function of Image History”, and assigned to IBM Corporation, generally relates to a method for generating a minimum length code word stream for efficient transmission or storage of two dimensional gray scale image data utilizing the concepts of adaptive differential pulse code modulation (PCM).        19. U.S. Pat. No. 4,417,276 to Bennett et al., entitled “Video to Digital Converter”, generally relates to a method for converting video signals to digital values and for storing these values in memory. Successive images are continuously digitized and adjacent picture elements are compressed to produce a spacially compressed image which takes up less memory space.        
While the video digitization and compression techniques disclosed in the foregoing patents have proven to be adequate for their intended purposes, there is no teaching of a Program Delivery System (PDS) which is capable of simultaneously delivering multiple signals from different origins or sources, such as video, audio and/or data. The PDS should also allow program suppliers to provide multiple programs per transponder channel, such as a satellite transponder channel, to cable, television or other systems headends or end users. One application for the PDS should be to provide multiple video outputs with multiple audio channels and VBI text signals for each video output. Another application of the PDS should be to provide various degrees of compression for different combinations of video, audio and/or data signals.
Therefore, it would be desirable to have a new Program Delivery System which will be compatible with digital or analog compression distribution requirements of cable, television and satellite systems.